1. Field of the Invention
The invention relates to a pn-luminescent or laser diode having an emission area in the semiconductor body of the diode defined by lateral boundries of a pn-junction and somewhat more particularly to a method of producing such diodes wherein a plurality of semiconductor layers are epitaxially deposited on a substrate body or on one another and electrodes are provided thereon.
2. Prior Art
The production of luminescent diodes having a laterally tightly limited area of a region (layer) present within the semiconductor body for light emission itself and which can be activated for radiation generation is known. In accordance with the prior art, the limitation of such area in the semiconductor body occurs by providing a layer sequence having a multiple alternating conductivity and which includes at least one inhibiting pn-junction. This inhibiting junction of the layer sequence is, however, omitted at the location where the limited, activated zone or luminescent surface area is to be present in the semiconductor body. A method of producing such known luminescent diode consists essential of a first step in which an epitaxial growth or deposition of at least one semiconductor layer (which can be doped to exhibit a desired conductivity) on the substrate body occurs. Next, the coated substrate body is removed from the epitaxy apparatus and is subjected to an etching process in which a portion of the epitaxially deposited layer is removed. Then the resultant substrate body is again placed into the epitaxy apparatus and further necessary layers, known per se, of the remaining layer sequence are deposited on the layer already applied before the intervening etching process and on the surface areas which were generated during the etching step. In this regard, attention is directed to an article by J. Heinen et al in "NTZ," Vol. 31, No. 2, (1978) pages 129-130, particularly FIG. 2 thereof. This type of known luminescent diode, just like the diode produced in accordance with the principles of the invention, is, because of the laterally confining luminescent surface therein, particularly well suited for coupling to a glass fiber for optical beam transmission (as is illustrated in FIG. 1 of the above-referenced publication). The structure illustrated at FIG. 2 of this publication shows the presence of a pn-junction which is situated next to or around an etched depression, there having a 50 .mu.m diameter. This etched area or depression determines and defines the earlier discussed active emission zone or the luminous surface of the diode. The remaining layers comprised of n-gallium-aliminum-arsenide and p-gallium-aluminum-arsenide shown at FIG. 2 of this publication form the further known layer sequence. This layer sequence can also be provided for diodes manufactured in accordance with the principles of the invention. Analogous steps for providing the electrodes for power supply shown there can also be used in the practice of the invention.